A SCAS is used to superimpose an order generated by the flight computer (i.e. the “autopilot”) onto a manual input (e.g. a pilot input). The SCAS comprises an actuator that provides an output for controlling a flight-control surface, such as a yaw rudder.
Traditionally, SCAS actuators comprise an assembly including a solenoid valve, an electro-hydraulic servo valve, a position sensor (such as a Linear Variable Differential Transformer (LVDT)) and an output piston.
This prior art system can however be complicated, expensive and prone to leakages due to the presence of the hydraulics in the servo valve.
The present disclosure seeks to address at least some of these issues.